That chap who ran the snowdonian marathon talks about his experiences on the barefoot running website, If I remember correctly it was on the yahoo forum.
personally I wouldn't run barefoot all the time but I think it is a useful training tool to get yourself running with the correct posture and to foot strike properly - as they say on the barefoot website if you jumped off a ladder would you land on you heels? Running barefoot forces you to adopt a mid foot strike, but more importantly teaches you how to run softer if that makes any sense.
Has anyone had experience with these:
http://www.vibramfivefingers.com/
They look great but they are a tad pricey.